Measured time delay and re-synchronization time in digital microwave radio systems

The transition from analog to digital transmission systems has been slower for electric power utilities than other industrial sectors because of concern that digital transmission system delay times could adversely impact the response time of transfer trip protective relaying equipment. Alcatel Network Systems has completed a comprehensive testing program to measure the absolute time delay and various re-synchronization times through analog and digital transmission systems. The general conclusion is that the worst case absolute time delay of 577 microseconds, VF to VF, through the digital microwave system is approximately one half the delay for a typical analog system. Absolute time delays of 500-600 microseconds should cause no problems to transfer trip protective relaying systems.<
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